1. Field of the Invention
The present invention relates to a liquid crystal device, more particularly, to a liquid crystal device using a carbon film as an alignment film for liquid crystal molecules, a manufacturing apparatus of the liquid crystal device, a manufacturing method of the liquid crystal device and a forming method of the alignment film.
2. Discussion of Related Art
A liquid crystal device has been widely used in recent years, and an application range thereof has been increasingly spread. In general, the liquid crystal device is constituted by electrodes formed of a transparent electrode material such as ITO on a transparent substrate such as glass, liquid crystal molecules are filled between the substrate having the electrodes formed thereon and an opposed substrate, and sealed by a sealing material. On a side of the electrode formed on the substrate, the side facing to the liquid crystal molecules, an alignment film that consists of a material such as a polyimide film and a carbon film is typically formed so that molecules of the liquid crystal can be aligned in the vicinity of the substrate to impart optical characteristics required to the liquid crystal device.
Description will be made for the case of manufacturing such an alignment film. In the case of using an organic film that consists of polyimide or the like, a polyimide precursor such as polyamic acid is coated on a transparent electrode, the polyamic acid is pre-baked, and then cured to form a polyimide film. Since the polyimide film thus formed is not still fully capable of aligning the liquid crystal molecules, a process of rubbing is required to align the liquid crystal molecules.
On the other hand, in the case of forming an alignment film with an inorganic material such as the carbon film, alignment treatment needs to be performed for the carbon film by irradiating with an ion beam (IB) in order to impart a sufficient alignment property thereto, after the carbon film is formed on the transparent electrode by a method such as evaporation, CVD and sputtering. As described above, when the organic film such as the polyimide film or the inorganic film such as the carbon film is used as the alignment film, two different processes, that is, deposition and alignment processing are required in any case, resulting in much process wastefulness from the viewpoint of cost and yield in manufacturing of the liquid crystal device.
As alignment films used in a liquid crystal display, other than the one using the above-described materials, the polyimide film, the carbon film including various structures and the like are proposed. For example, there is also made an attempt, in which a transparent material such as a silicon oxide film and a nitride film is deposited obliquely onto the substrate, and the liquid crystal is aligned by use of a shape of the transparent material physically formed. However, the alignment film formed by such oblique deposition has a too large pretilt angle and a weak anchoring energy (alignment force), thus the alignment film has not been practically used under the present conditions.
The present invention was made in consideration of the above-described problems. The object of the present invention is to provide a liquid crystal device that uses a carbon film including a structure by which liquid crystal molecules can be aligned simultaneously by deposition, the liquid crystal device being manufactured without passing through the two steps of process as described above, an apparatus for manufacturing the liquid crystal device, a manufacturing method of the liquid crystal device and an alignment film forming method.